The present invention relates generally to fastener-driving tools, and more particularly to a new and improved seal adaptor which is structured so as to effectively interface between the outwardly projecting valve stem of a metering valve operatively associated with a fuel cell power supply for the fastener-driving tool, and a tool stem of the fastener-driving tool whereby secure sealed conditions are always maintained between the metering valve stem and the tool stem regardless of the disposition or orientation of the fuel cell with respect to the tool during the normal operative cyclical firing of the fastener-driving tool.
Fuel cells are conventionally used as a power supply or a source of power for fastener-driving tools. Examples of fuel cells, and fastener-driving tools utilizing the same, are disclosed within U.S. Pat. No. 5,115,944 which issued to Nikolich on May 26, 1992, U.S. Pat. No. 4,522,162 which issued to Nikolich on Jun. 11, 1985, U.S. Pat. No. 4,483,474 which issued to Nikolich on Nov. 20, 1984, U.S. Pat. No. 4,483,473 which issued to Wagdy on Nov. 20, 1984, and U.S. Pat. No. 4,403,722 which issued to Nikolich on Sep. 13, 1983.
Briefly, as illustrated within FIG. 1, a typical fuel-cell powered fastener-driving tool is partially disclosed and is generally indicated by the reference character 10. The tool 10 comprises a combustion chamber 12 within which an air-fuel mixture distribution fan 14 is disposed, and a fuel charge conduit 16 is defined within the head 18 of a cylinder block 19. The fuel cell is disclosed at 20 and is provided with a dispensing valve unit 22. Dispensing valve unit 22 has, in turn, a metering valve unit 24 operatively connected thereto wherein the latter is adapted to discharge, dispense, or inject a predetermined amount or dosage of fuel from the fuel cell 20 into the tool combustion chamber 12 each time a fastener-driving and firing operational cycle is initiated. The metering valve unit 24 comprises a valve stem 26, and the tool 10 further comprises a tool stem 28 which is fluidically connected at one end thereof to the fuel charge conduit 16, and is operatively engaged at its opposite end to the metering valve stem 26 so as to provide a fluidic flow path from the fuel cell 20, the dispensing valve unit 22, and the metering valve unit 24 into the tool combustion chamber 12. As best seen further in FIGS. 2 and 3, the tool stem 28 comprises a axial stem portion 30 which is provided with an axial bore 32 defining a fluid passageway for the fuel to be dispensed into the tool combustion chamber 12, and a head end portion 34 which is adapted to be engaged with the free end portion of the metering valve stem 26. More particularly, the head end portion 34 of the tool stem 28 is provided with a counterbored region 36 within which the free end portion of the metering valve stem 26 is adapted to be received or seated.
This structural system operates substantially satisfactorily, however, since both the valve stem 26 and the tool stem 28 are fabricated either from, for example, a suitable plastic material or from a suitable metal material, the two components are operatively engaged with each other so as to effectively establish either a plastic-to-plastic contact or engagement interface or a metal-to-metal contact or engagement interface. Accordingly, a fluidically sealed interface between the valve stem 26 and tool stem 28 components is not in fact capable of being established.
In view of the fact that the valve stem 26 and tool stem 28 elements cooperate together so as to effectively form or establish the necessary fuel conduit interface, as well as the necessary fluidic sealing of such conduit interface as determined by means of the interengagement of such stem elements 26,28, high manufacturing tolerances are required in connection with the fabrication of such stem elements 26,28 in order to achieve, as best as possible, the aforenoted sealing function between the stem elements 26,28. Still further, the interengagement of the valve stem 26 and tool stem 28 components limits the necessary movements of the fuel cell 20 and the metering valve 24 components within the tool 10. Lastly, the constant or repetitive pivotal movements of the valve stem 26 with respect to the tool stem 28, as a result of the initiation of each successive fastener-firing operational cycle and while maintaining the aforenoted fluidic interface therebetween, causes the valve stem 26, as well as the tool stem 28, to undergo bending stresses or strains which can lead to structural fatigue, cracking, breakage, failure, and additional fuel leakage within the tool 10.
A need therefore exists in the art for a new and improved fuel cell powered fastener-driving tool, as well as a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem as a seal interface therebetween, wherein the auxiliary fuel cell metering valve stem seal adaptor will enable improved and reliable sealing to be achieved between the metering valve stem and the tool stem whereby such reliable sealing between such stem components can be ensured and maintained despite the normal tilted movements of the fuel cell during the initiation of each fastener-driving operational cycle. In this manner, fuel leakage internally within the tool can be effectively prevented. In addition, manufacturing tolerances of the components do not need to be as rigid, and the provision of the seal adaptor readily permits movement of the fuel cell and its operatively associated metering valve without inducing stresses and strains upon the metering valve stem-tool stem connection. Accordingly, fatigue, fracture, and failure of the components are eliminated with a consequent enhancement of the service life of the metering valve and tool stem components. Lastly, it is desirable to be able to achieve these various needs in the simplest and most cost-effective manner possible.
Accordingly, it is an object of the present invention to provide a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem of a fuel cell powered fastener-driving tool.
Another object of the present invention is to provide a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem of a fuel cell powered fastener-driving tool wherein the operational drawbacks and deficiencies of conventional operative engagement structure defined between the metering valve stem and the tool stem of PRIOR ART fuel cell powered fastener-driving tools can effectively be overcome.
An additional object of the present invention is to provide a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem of a fuel cell powered fastener-driving tool wherein enhanced sealing characteristics or properties are able to be achieved between the metering valve stem and the tool valve stem.
A further object of the present invention is to provide a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem of a fuel cell powered fastener-driving tool wherein enhanced sealing characteristics or properties are able to be achieved between the metering valve stem and the tool valve stem such that fuel leakage internally within the fastener-driving tool is effectively prevented.
A last object of the present invention is to provide a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with the fuel cell metering valve stem and the tool valve stem of a fuel cell powered fastener-driving tool wherein enhanced sealing characteristics or properties are able to be achieved between the metering valve stem and the tool valve stem such that bending stresses, strain, and fatigue are no longer impressed upon the metering valve stem and the tool stem components so as to respectively enhance the service lives thereof.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved auxiliary fuel cell metering valve stem seal adaptor for use in conjunction with a fuel cell metering valve stem and a tool valve stem, of a fuel cell powered fastener-driving tool, as a seal interface between the metering valve stem and the tool stem, wherein the seal adaptor comprises, in effect, an annular cap which is adapted to be mounted upon the free distal end portion of the metering valve stem. The seal adaptor is fabricated from a suitable elastomer material, it has a substantially cylindrical configuration, and the free sealing end of the seal adaptor has a substantially frusto-conical configuration wherein substantially the entire seal adaptor is adapted to be seated within a similarly configured recessed portion of the tool stem. Accordingly, the seal adaptor is readily capable of a combination of rotational and pivotal movements relative to the tool stem and attendant the activation of the metering valve in conjunction with a fastener-firing and discharge operational cycle, while nevertheless maintaining the desired sealed state between the metering valve stem and the tool stem.